Conductive Substrate Research Articles

A Computation-Guided Design of Highly Defined and Dense Bimetallic Active Sites on a Two-Dimensional Conductive Metal-Organic Framework for Efficient H2O2 Electrosynthesis.

Electrochemical synthesis of hydrogen peroxide (H2O2) via the two-electron oxygen reduction reaction (2e--ORR) provides an alternative method to the energy-intensive anthraquinone method. Metal macrocycles with precise coordination are widely used for 2e--ORR electrocatalysis, but they have to be commonly loaded on conductive substrates, thus exposing a large number of 2e--ORR-inactive sites that result in poor H2O2 production rate and efficiency. Herein, guided by first-principle predictions, a substrate-free and two-dimensional conductive metal-organic framework (Ni-TCPP(Co)), composed of CoN4 sites in porphine(Co) centers and Ni2O8 nodes, is designed as a multi-site catalyst for H2O2 electrosynthesis. The approperiate distance between the CoN4 and Ni2O8 sites in Ni-TCPP(Co) weakens the electron transfer between them, thus ensuring their inherent activities and creating high-density active sites. Meanwhile, the intrinsic electronic conductivity and porosity of Ni-TCPP(Co) further facilitate rapid reaction kinetics. Therefore, outstanding 2e--ORR electrocatalytic performance has been achieved in both alkaline and neutral electrolytes (>90 %/85 % H2O2 selectivity within 0-0.8 V vs. RHE and >18.2/18.0 mol g-1 h-1 H2O2 yield under alkaline/neutral conditions), with confirmed feasibility for water purification and disinfection applications. This strategy thus provides a new avenue for designing catalysts with precise coordination and high-density active sites, promoting high-efficiency electrosynthesis of H2O2 and beyond.

A Computation‐Guided Design of Highly Defined and Dense Bimetallic Active Sites on a Two‐Dimensional Conductive Metal–Organic Framework for Efficient H2O2 Electrosynthesis

AbstractElectrochemical synthesis of hydrogen peroxide (H2O2) via the two‐electron oxygen reduction reaction (2e−‐ORR) provides an alternative method to the energy‐intensive anthraquinone method. Metal macrocycles with precise coordination are widely used for 2e−‐ORR electrocatalysis, but they have to be commonly loaded on conductive substrates, thus exposing a large number of 2e−‐ORR‐inactive sites that result in poor H2O2 production rate and efficiency. Herein, guided by first‐principle predictions, a substrate‐free and two‐dimensional conductive metal–organic framework (Ni‐TCPP(Co)), composed of CoN4 sites in porphine(Co) centers and Ni2O8 nodes, is designed as a multi‐site catalyst for H2O2 electrosynthesis. The approperiate distance between the CoN4 and Ni2O8 sites in Ni‐TCPP(Co) weakens the electron transfer between them, thus ensuring their inherent activities and creating high‐density active sites. Meanwhile, the intrinsic electronic conductivity and porosity of Ni‐TCPP(Co) further facilitate rapid reaction kinetics. Therefore, outstanding 2e−‐ORR electrocatalytic performance has been achieved in both alkaline and neutral electrolytes (>90 %/85 % H2O2 selectivity within 0–0.8 V vs. RHE and >18.2/18.0 mol g−1 h−1 H2O2 yield under alkaline/neutral conditions), with confirmed feasibility for water purification and disinfection applications. This strategy thus provides a new avenue for designing catalysts with precise coordination and high‐density active sites, promoting high‐efficiency electrosynthesis of H2O2 and beyond.

Rapid and eco-friendly ultrasonic exfoliation of transition metal dichalcogenides supported on sonogel-nanocarbon black: A non-precious electrocatalyst for hydrogen evolution reaction

Recently, there has been growing interest in replacing expensive platinum-based catalysts with cost-effective non-precious metal alternatives for water electrolysis aimed at hydrogen production. This study introduces an innovative, green, and cost-effective strategy for the development of non-precious electrocatalysts by leveraging sodium alginate-mediated ultrasonic exfoliation to produce transition metal dichalcogenide (TMD) nanosheets. These nanosheets are supported on Sonogel-Carbon electrodes (SGC), providing a novel conductive base for HER catalysis. Using a diverse array of TMD materials, including MoS2, MoSe2, WS2, and WSe2, we assess their catalytic activity towards HER. The study demonstrates significantly enhanced HER performance through bulk modification of the electrodes with nanocarbon black (SGC-CB). This enhancement is primarily due to the synergistic effects of improved electron transfer and increased active site availability, facilitated by the unique structural properties of the exfoliated TMD nanosheets and the conductive Sonogel-Carbon substrate. Notably, the optimized MoSe2NS-SGC-CB configuration achieves an exceptional overpotential of 240 mV at a current density of 10 mA/cm2, surpassing conventional bulk catalysts and highlighting the potential of sodium alginate as a viable dispersing agent for the large-scale production of TMD nanosheets. The operational stability and cost-effectiveness of this electrocatalyst, combined with its environmental friendliness, mark a significant step forward in the pursuit of sustainable hydrogen fuel production technologies.

Biomimetic Hierarchies for Universal Surface Enhancement and Applications in Water Treatment.

Hierarchical superstructures, ubiquitously found in nature, offer enhanced efficiency in both substance reaction and mass transport owing to their unique multiscale features. Inspired by these natural systems, this research reports a general and scalable electrochemical scheme for creating highly branched, multilevel porous superstructures on various electrically conductive substrates. These structures exhibit cascading features from centimeters, submillimeters, micrometers, down to sub-100 nm, significantly increasing the surface area of substrates, such as foams, foils, and carbon cloth by 2 orders of magnitude─among the highest reported enhancements. This versatile and low-cost method, applicable to a range of electrically conductive substrates, enables innovative flow-assisted water purification with enhanced energy efficiency. The performance, successfully removing 99% of mercury within 0.5 h at 540 rpm and meeting the U.S. Environmental Protection Agency (EPA) safety standards for drinking water, further validates the advantages of these unique structures. Overall, the reported general, economical, and versatile scheme could broadly impact energy and environmental remediation.

3D Printed Leaf-Vein-Like Al2O3/EP Biohybrid Structures with Enhanced Thermal Conductivity.

The high computility of electronic components put urgent requirements on the dissipation efficiency of a high thermal conductive substrate. Herein, inspired by the nature structure, leaf-vein-like Al2O3 skeleton was first designed though topology optimization algorithm and manufactured via vat photopolymerization (VPP) 3D printing, then compounded with epoxy (EP) to prepare leaf-vein-like biohybrid structures. The biohybrid structure had a high λ (14.65 Wm-1 K-1 with the solid fraction of 40 vol %), which was 5585% higher than neat EP and 269% higher than the random dispersed Al2O3/EP composite at the same solid amount. Moreover, it further showed a high enhancement in the cooling ecoefficiency of the lighting-emitting diode (LED) cooling system. Compared with 40 vol % random dispersed Al2O3/EP composite as a cooling substrate, the leaf-vein-like biohybrid structure with the same solid fraction reduced the working temperature of LED by 8.9 °C. Our strategy has a significant potential as a viable type and mass-producible bionic cooling substrate.

Chinese ink-coated elastic PU/PET fibers as multifunctional flexible wearable sensors

Textiles as conductive substrates are widely used in sensing applications due to their good elasticity, high stretchability and recoverable deformation. Here, the mask rope (polyurethane/polyester blended fibers) was selected as flexible substrate to load of conductive Chinese ink using surface swelling technique in N, N-dimethylformamide. The presence of carbon nanoparticles in the ink imparts electrical conductivity to the elastic fiber while maintaining the mechanical properties and extensibility of the fiber. This simple and low-cost method allows excellent interfacial adhesion between the conductivity ink layer and the elastic fibers, and the carbon particles do not fall off even when the modified fiber was treated by sonication in water. The ink coated elastic fiber as strain sensor shows excellent stability and sensitive responsiveness after 500 stretch-release cycles. The response and recovery times during the sensitivity experiment of the flexible fiber sensor are 133.79 and 134.76 ms. The sensor exhibits physiological motion detection and quality monitoring capabilities, which can accurately monitor human movements such as walking, wrist movement, throat swallowing and articulation. The sensor also has a good Joule heating effect, and the temperature of the conductive fiber can increase 88.9°C in the 60s under 15V voltage. This work develops a simple and efficient, low-cost, mass-producible flexible sensor with potential for physiological activity, temperature, and humidity detection.

Three-component NiO/Fe3O4/rGO nanostructure as an electrode material towards supercapacitor and alcohol electrooxidation

A nanocomposite made of nickel oxide and iron oxide (NiO/Fe3O4) and its hybrid with reduced graphene oxide (rGO) as a conductive substrate with a highly functional surface (NiO/Fe3O4/rGO) was synthesized using a simple hydrothermal approach. This study addresses the challenge of developing efficient materials for energy storage and alcohol fuel cells. After confirming the synthesis through structural analysis, the potential of these nanocomposites as supercapacitor electrodes and catalysts for methanol and ethanol oxidation in alcohol fuel cells were evaluated. The synergy of combining the two metal oxides and adding rGO to the composite structure led to excellent electrocatalytic activity in alcohol oxidation. For the modified NiO/Fe3O4/rGO electrode in the methanol oxidation reaction (MOR), a current density of 450 mA/cm2 at 0.67 V and excellent catalyst stability of 98.7% over 20 hours in chronoamperometric analysis were observed. In the ethanol oxidation reaction (EOR), an oxidative current of 235 mA/cm2 at a peak potential of 0.76 V was seen, with catalyst stability of 96.4% after 20 hours. As a supercapacitor electrode, the NiO/Fe3O4 composite demonstrated a specific capacitance of 946 F/g, while NiO/Fe3O4/rGO showed 1155 F/g. The stability of these electrodes after 10000 GCD cycles was 83.6% and 90.6%, respectively. These findings suggest that the proposed structures are cost-effective and reliable alternatives for energy storage and production, suitable for alcohol fuel cells and supercapacitors.

Direct writing of calcium phosphate/graphite nanocomposite film using laser-induced graphitization of polyimides

We report the direct writing of calcium phosphate/graphite nanocomposite using laser-induced graphitization of suspension-covered polyimide (PI) films. Calcium phosphate/graphite nanocomposites are desirable for the osteoconductive, osteoconductive, and resorptive properties of calcium phosphate and the electrical conductivity of graphitic carbon. Two forms of calcium phosphate, namely, EggCaP and CaOP, were synthesized by chemomechanical alloying of diammonium hydrogen phosphate (DHP) with eggshells – a waste material – and reagent-grade calcium oxide (CaO) powders, respectively. Fourier transform infrared (FTIR) spectroscopy of the synthesized powders revealed the phase change of starting materials to calcium phosphates (CaP), and powders were suspended in methanol to form printing suspension. Laser irradiation of synthesized CaP powder suspension-covered polyimide (PI) surfaces resulted in the formation of electrically conductive films due to laser-induced graphitization of PI. Laser-induced graphited films based on EggCaP suspension (ELIG) and CaOP (CLIG) had a sheet resistance of 25 Ω/∎ and 30 Ω/∎, respectively, and had lower resistance than the LIG films formed from bare PI (60 Ω/∎). Raman spectroscopy revealed that repeated laser irradiation of ELIG and CLIG film led to decreased defects and higher graphitization. ELIG had an ID/IG ratio of 0.65 after the first irradiation, but repeated irradiation reduced the ratio to 0.38. Similarly, CLIG had a higher ID/IG ratio of 0.55 during the first irradiation, and repeated irradiation reduced it to 0.42. Furthermore, CO, CO stretch modes, and various PO4 groups were also found in the Raman spectrum, indicating the formation of CaP/graphite nanocomposites in the graphitized films. SEM results showed that both graphitized films had closed foam-like microstructure with CaP particles deposited on the pore walls. Films formed after single irradiation had discrete CaP particle deposits on the surface, but repeated laser irradiation led to the integration of CaP particles into the pore walls. The ELIG films showed higher incorporation of the CaP particles and the highest electrical conductivity. The laser-induced graphitic transformation leads to incorporating the CaP particles into a conductive substrate, resulting in a CaP/graphite nanocomposite. The high electrical conductivity, closed-foam-like microstructure, porosity, biocompatibility, and hierarchical surface roughness of the ELIG and CLIG films make them attractive for biosensors, bioelectronics, and implant applications.

Highly durable and conductive Korea traditional paper (Hanji) embedded with Ti3C2Tx MXene for Hanji-based paper electronics

Lightweight, low-cost, eco-friendly, and mechanically flexible Ti3C2Tx (MXene) electrodes require for paper electronics. We develop a highly durable and conductive traditional Korean paper (Hanji) covered with MXene for Hanji-based paper electronics. The effective networking of MXene on the cellulose structure of Hanji leads to a highly conductive and flexible Hanji which acts as a multi-functional paper for Hanji-based paper electronics. Owing to the synergetic combination of Hanji and MXene, the as-prepared Hanji/MXene exhibits a low sheet resistance of 0.62 Ohm square−1, and outstanding mechanical stability without breaking the Hanji fibers. To further evaluate the potential of our Hanji/MXene composite, its performance in electromagnetic interference (EMI) shielding, interconnectors, heaters, supercapacitors, and temperature sensor applications is investigated. Shielding and heater paper samples employing Hanji/MXene-based electrodes show an EMI shielding efficiency (EMI SE) of 43.3 dB and saturation temperature of 76 °C at a low voltage of 3 V. Moreover, the Hanji/MXene-based supercapacitors exhibit a capacitance of 139.6 mF cm−2 at a current density of 1 mA cm−2. Furthermore, the Hanji/MXene-based temperature sensors exhibit an effective sensing performance over a wide temperature range. Overall, the successful operation of Hanji-based EMI shielding devices, interconnectors, heaters, supercapacitors, and temperature sensors indicates that Hanji/MXene serves as a promising conductive paper substrate for multi-functional paper electronics.

Two-dimensional vanadium carbide (V2C) MXene derived heterostructures for high-performance lithium storage

Li3VO4 is notable for its high theoretical capacity and favorable lithium-ion insertion potential, making it a promising candidate for lithium storage applications. However, its practical use is limited by low electronic conductivity, which results in reduced electrochemical performance and significant resistance polarization during lithium storage. Herein, we developed a Li3VO4/V2CTx heterostructure using a MXene-derived approach, where Li3VO4 is anchored onto a conductive V2CTx MXene substrate. Theoretical calculations suggest that the heterostructure exhibits enhanced lithium adsorption capabilities compared to V2CTx, indicating improved interactions with lithium ions. The synthesized Li3VO4/V2CTx heterostructure demonstrates excellent rate performance and cycling stability. Additionally, a lithium-ion capacitor utilizing this heterostructure as the anode and activated carbon as the cathode achieves impressive power density and energy density. This study underscores the potential of this heterostructure as a high-performance anode material and offers valuable insights for the design of other advanced electrode materials.

An Artificial Leaf with Patterned Photocatalysts for Sunlight-Driven Water Splitting.

Plant leaves can turn entirely absorbed light into chemical energy due to their spatially separated photosystems I and II in the thylakoid membrane that enables unidirectional Z-scheme type charge transfer between them. In artificial systems that mimic leaves, a lack of spatial and interfacial control of active units (i.e., hydrogen evolution photocatalyst/HEP and oxygen evolution photocatalyst/OEP) introduces competitive charge transfer channels between them, resulting in deficient Z-scheme type charge transfer. Herein, we demonstrate that a patterned photocatalyst sheet, namely, an artificial leaf, comprising an ordered and separated distribution of the OEP and HEP strips on a conductive substrate, achieves unidirectional Z-scheme type charge transfer as the leaves do. It represents a next-generation photocatalytic system that mimics the leaves to bring breakthrough in photocatalytic over water splitting performance with the combination of highly active HEP and OEP photocatalysts, opening up a promising avenue toward solar energy conversion by artificial photosynthesis.

Direct Detection of the Magnetic Force and Field Coupling of Electronic Spins Using Photoinduced Magnetic Force Microscopy.

The intrinsic spin of the electron and its associated magnetic moment can provide insights into spintronics. However, the interaction is extremely weak, as is the case with the coupling between an electron's spin and a magnetic field, and it poses significant experimental challenges. Here we demonstrate the direct measurement of polarized single NV- centers and their spin-spin coupling behaviors in diamond. By using photoinduced magnetic force microscopy, we obtain the extremely weak magnetic force coupling originating from the electron spin. The polarized spin state of NV- centers, transitioning from |0⟩ to |±1⟩, and their corresponding Zeeman effect can be characterized through their interaction with a magnetic tip. The result presents an advancement in achieving electron spin measurements by magnetic force, avoiding the need for manufacturing conductive substrates. This facilitates a better understanding and control of electron spin to novel electronic states for future quantum technologies.

Novel design of nickel cobalt boride nanosheets-decorated molybdenum disulfide hollow spheres as efficient battery-type materials of hybrid supercapacitors

Transition metal borides (TMBs) with high theoretical capacitances and excellent electronic properties have attracted much attention as a promising active material of supercapacitors (SCs). However, TMB nanoparticles are prone to conduct self-aggregation, which significantly deteriorates the electrochemical performance and structural stability. To address the severe self-aggregation in TMBs and improve the active material utilization, it is imperative to provide a conductive substrate that promotes the dispersion of TMB during growths. In this work, sheet-like nickel cobalt boride (NCB) was grown on molybdenum disulfide (MoS2) hollow spheres (H-MoS2) by using simple template growth and chemical reduction methods. The resultant NCB/H-MoS2-50 was observed with uniform NCB nanosheets structure on the surface of the H-MoS2 and stronger MB bonding. After optimizing the loading amount of H-MoS2, the optimal composite (NCB/H-MoS2-50) modified nickel foam (NF) exhibits a superior specific capacity (1302 C/g) than that of the NCB electrode (957 C/g) at 1 A/g. Excellent rate capability of 84.8% (1104 C/g at 40 A/g) is also achieved by the NCB/H-MoS2-50 electrode. The extraordinary electrochemical performance of NCB/H-MoS2-50 is credited to the unique nanosheet-covered hollow spheres structure for facilitating ion diffusion and versatile charge storage mechanisms from the pseudocapacitive behavior of H-MoS2 and the Faradaic redox behavior of NCB. Furthermore, a hybrid SC is assembled with NCB/H-MoS2-50 and activated carbon (AC) electrodes (NCB/H-MoS2-50//AC), which operates in a potential window up to 1.7 V and delivers a high energy density of 76.8 W h kg−1 at a power density of 850 W kg−1. A distinguished cycling stability of 93.2% over 20,000 cycles is also obtained for NCB/H-MoS2-50//AC. These findings disclose the significant potential of NCB/H-MoS2-50 as a highly performed battery-type material of SCs.

Multiphase lattice engineering of bimetallic phosphide-embedded tungsten-based phosphide/oxide nanorods on carbon cloth: A synergistic and stable electrocatalyst for overall water splitting

The hierarchical design of the three-dimensional (3D) nanoarchitecture, comprising multiple phases within an interconnected network on a conductive substrate, offers a high specific surface area, abundant exposed active sites, and rapid electron transport. In our study, we synthesized a hybrid catalyst by integrating (Fe,CO)-P nanoparticles into uniformly grown W-(O,P) nanorods on carbon cloth (CC) using a straightforward method, demonstrating notable electrocatalytic performance. The as-synthesized (Fe,CO)-P/W-(O,P)@CC exhibited remarkable performance in both the oxygen evolution reaction (OER) and the hydrogen evolution reaction (HER) for overall water splitting. It achieves overpotentials of 210 and 61.3 mV for the OER and HER, respectively, at a current density of 10 mA cm−2 in a 1 M KOH solution. As a bifunctional electrocatalyst in overall water splitting, (Fe,CO)-P/W-(O,P)@CC needs only 1.50 V to attain a current density of 10 mA cm−2, surpassing traditional Pt/C@CC and IrO2@CC counterparts (1.53 V @ 10 mA cm−2). The synergistic effects between (Fe,Co)-P and the W-(O,P)@CC nanohybrid heterostructure enhance the charge transfer, further promoting the activity of this hybrid electrocatalyst. This study reveals a promising avenue for advanced water electrolysis applications.

Lab-on-a-chip paper-based electrochemically assisted solid-phase microextraction and ion selective sensor for determination of naproxen in biological fluid samples

BackgroundThe integration of paper-based analytical devices with lab-on-a-chip technology has opened up new possibilities for miniaturized, rapid, low cost and portable diagnostic testing in resource limited settings. This work introduces an integrated lab-on-a-chip platform coupling paper-based analytical devices (LOC-PADs) for dual usage: electrochemically controlled solid-phase microextraction (EC-SPME) and determination of naproxen (NAP) by potentiometric ion-selective electrode (ISE) in biological samples. ResultsConductive papers were successfully fabricated by a chemical procedure. Thereupon, a conducting molecularly imprinted polymer (CMIP) film based on PPy and an anionic model drug (NAP) as a template were applied to the conductive paper substrate via electrochemical methods. A microfluidic chip device was employed to assess the analytical performance of the fabricated paper-based CMIP. The designed chip is divided into two parts with a microfluidic channel between them. The first chamber is an extraction zone for EC-SPME of NAP by using the CMIP paper as a selective sorbent. The second chamber is the detection zone and consists of a paper-based NAP ion selective sensor for potentiometric detection of drug. The analytical process was investigated and optimized for each chamber. Remarkable selectivity towards NAP was achieved in the concentration range from 4.0 × 10−7 to 1.0 × 10−2 mol L−1 with determination coefficient (R2 = 0.99) and the limit of detection (LOD) was 2.0 × 10−7 mol L−1. Anionic Nernstian compliance was gained −58.5 ± 0.5 mV decade−1, and response time in the detection step was 7s for ISE. Satisfactory spiking recovery values within the acceptable range of 90–110 % with RSDs ≤7 % were achieved for the analysis of real samples with fully portable LOC device. SignificanceThe LOC-PADs were favorably used for selective extraction and determination of NAP in serum and saliva samples, respectively. EC-SPME caused sample clean-up, reduced or eliminated different interferences and enhanced selective response of ISE as detection zone of device. Integration of EC-SPME and ISE in a single chip enabled easy and fast determination of trace amounts of NAP in limited real sample volumes, and fully portable advantages.

Copper-Surface-Mediated Synthesis of sp2 Carbon-Conjugated Covalent Organic Framework Photocathodes for Photoelectrochemical Hydrogen Evolution.

Sp2-carbon (sp2-c) covalent organic frameworks (COFs), featuring distinctive π-conjugated network structures, facilitate the migration of photo-generated carriers, rendering them exceptionally appealing for applications in photoelectrochemical water splitting. However, owing to the powdery nature of COFs, leaving anchor the sp2-c COFs powder tightly onto a conductive substrate challenging. Here, we propose a method for preparing photoactive substance-conductive substrate integrated photocathodes through copper surface-mediated knoevenagel polycondensation (Cu-SMKP), this approach results in a uniform and stable sp2-c COF film, directly grown on commercial copper foam (COFTh-Cu). The COFTh-Cu demonstrates a high H2-evolution photocurrent density of 56 μA cm-2 at 0.3 V vs. RHE, sustaining stability for 12 h. The as-prepared COFTh-Cu represents a 4.5-fold increase in current density compared to traditional spin-coating methods and outperforms most COF photocathodes without cocatalysts. This innovative copper surface-mediated approach for preparing photocathodes opens up a crucial pathway towards the realization of highly active COF photocathodes.

The comprehensive understanding of intrinsic contribution of nickel foam as a conductive substrate in water splitting

Using nickel foam as a substrate for an electrocatalyst to report overpotential in a manuscript is a popular method in electrochemical testing or water-splitting i.e., the oxygen evolution reaction (OER) and the hydrogen evolution reaction (HER). However, use of coated Nickel foam as substrate methodology is, in essence, not reasonable for studying the intrinsic chemistry difference of electrocatalysts. To assess water-splitting devices, Ni-foam is a valid substrate if nanoparticles are grown uniformly; however, when drop-casted ink methodology is used or there is inhomogeneous growth of nanoparticles, it becomes difficult to determine whether a particular electrocatalyst is intrinsically active or not. In order to gain a rational understanding of the electrochemical activity and overpotential findings of a specific catalyst, it is essential to recognize the limitations of Ni-foam in reflecting its intrinsic role in electrocatalytic activity. In this study, the same catalyst was drop-casted on three different substrates, namely glassy carbon electrode (GCE), carbon fiber paper (CFP) and nickel foam (NF). It was observed that electrochemical results, such as overpotential, Tafel slope, turnover frequency, and others, varied significantly between NF and CFP or GCE. Therefore, it is concluded that NF should not be preferred as a conductive substrate during electrochemical testing (ET). On the contrary, other neutral substrates like CFP and GCE should be employed.

Boosting the capacitive property of binary metal tellurium of MnCoTe/NiFeTe yarn coils-like through surface engineering for high-performance supercapacitors

Improving the performance of electrode materials based on transition metals can significantly push advancements in energy storage devices. In this work, we offer a novel in situ tellurization approach to synthesize brand-new decorated yarn-coils MnCoTe/NiFeTe on a NiF (labeled MCTe/NFTe@NiF) which makes them attractive candidates for electrode materials in hybrid supercapacitors. At first, two consecutive hydrothermal methods were used to create electrode materials MnCo-LDH and MnCo-LDH/NiFe-LDH on nickel foam, respectively. In the following, electrode material MnCo-LDH/NiFe-LDH was subjected to a tellurization process to create MnCoTe/NiFeTe nanostructures. The direct growth strategy of electrode materials on a conductive substrate (NiF) effectively eliminates the need for polymer binder or conductive materials, thereby facilitating the redox process. The MnCoTe/NiFeTe@NiF electrode benefits from the synergistic effects of conductive tellurium and yarn coils-like morphology, resulting in faster electron/ion transport, increased efficiency, and superior electrochemical performance. The MCTe/NFTe@NiF electrode reveals highly desirable electrochemical characteristics, including a specific capacity of 223.36 mA h/g at 1 A/g, and reliable longevity surpassing 10,000 GCD cycles, with maintaining 73.18 % of its initial specific capacity at 30 A/g. We have prepared a hybrid supercapacitor (labeled MCTe/NFTe@NiF(+)//AC@NiF(−)), which utilizes the positive MCTe/NFTe@NiF and the negative AC@NiF electrodes. This hybrid supercapacitor indicated an excellent energy density of 51.55 Wh/kg, a power density of 799.98 W/kg, and showed substantial longevity (92.33 % after 10,000 GCD cycles).

Utilization of in-situ self-supporting materials for the preparation of flexible and stretchable electrodes for the detection of nitric oxide released from cells

Real-time monitoring of nitric oxide from endogenously cells released is crucial for revealing their physiological activities or pathological processes. However, designing electrochemical sensors for real-time monitoring at the cellular level is challenging due to the simultaneous requirements of sensitivity, transient recording capability, and biocompatibility. Combining the universally self-supported grown highly active materials with stretchable conductive flexible substrates holds promise for achieving sensitive detection of cells and real-time monitoring of mechanically induced biomolecular release. However, existing manufacturing strategies for highly sensitive stretchable flexible electrochemical sensors still face significant challenges due to low material activity, high processing requirements, and the complexity of further designing membrane electrodes. Here, we designed a method of in-situ self-supported growth to grow Co-doped Ni(OH)2 structures on rigid Ti foil. Leveraging the synergistic effect of Co and Ni, sensitive detection of NO was achieved, enabling real-time monitoring of trace amounts of NO released by Raw 264.7 cells. Based on this material, using catalytic ink method, it was transferred to low-resistance flexible ITO film (LIF), enabling real-time monitoring of mechanically induced NO release from Human Umbilical Vein Endothelial Cells (HUVECs) cells.

Simplifying perovskite solar cell fabrication for materials testing: how to use unetched substrates with the aid of a three-dimensionally printed cell holder.

This work demonstrates that unetched substrates can be reliably used in perovskite solar cell (PSC) fabrication. Chemical etching and laser patterning of the bottom electrodes are time- and resource-consuming processes. In particular, when testing novel conductive substrate materials, such as metallic or bio-based substrates, etching or patterning could be entirely unfeasible or could require significant process optimization. Avoiding these steps could accelerate research on PSCs, yet the literature shows no attempts to override these steps. Here, PSCs were fabricated and characterized using three-dimensionally printed holders with spring-loaded pins. We show that devices made on unetched substrates have, on average, a similar performance to those made on etched substrates (16 ± 1% and 16.0 ± 0.7%, respectively). Our study provides a new strategy for fabricating PSCs, particularly when etching and laser patterning are impractical.